Until recently, it was believed that multisensory integration begins in high-level cortical regions, after protracted hierarchical processing within each unisensory system. Results in the prior project period refute this view. The hypothesis driving our competing renewal application incorporates low-level multisensory processing with that occurring in higher-order multisensory regions. The pervasiveness of low-level integrative operations is staggering. Among recent findings showing direct anatomical connections between A1 and V1, and a wealth of low-level influences on auditory processing, is the remarkable ability of non-auditory inputs to control the pattern of ongoing neuronal activity in auditory cortex. This is fundamentally significant because ongoing neuronal activity sets the context within which incoming sensory inputs are processed. Our preliminary data make several key predictions about the manner in which context is controlled, and about the way that it in turn controls sensory processing. Our long-term goal is to define the mechanisms of multisensory interactions in auditory cortex, and their contributions to the auditory functions of the region. Our specific aims are: 1. To consolidate and extend our understanding of the functional properties, areal distribution and anatomical mechanisms of visual, as well as somatosensory inputs in auditory cortex. 2. To determine how ongoing oscillatory dynamics control the both unisensory (e.g., auditory) and multisensory integration in auditory cortex. 3. To investigate how auditory cortical dynamics are addressed by attention and discrimination. Because of our unique combination of methods we can bridge the gap between incisive findings from in-vitro cellular-level experiments and effects noted by electromagnetic and hemodynamic imaging studies in humans.